An automatic switching type winding withstand voltage test system and method for a mutual inductor

Abstract

The present application belongs to the field of mutual inductor manufacturing, and particularly relates to an automatic switching type winding withstand voltage test system and method for mutual inductor, which comprises a power switch, a voltage regulator, a test transformer, a winding switching system, an ammeter A1, an ammeter A2, a voltmeter V1 and a voltmeter V2; the voltage regulator is connected to the power supply, and the primary winding of the voltage regulator is connected to the input end of the primary winding of the test transformer through the ammeter A1; the secondary winding of the test transformer is connected to the high-voltage line in sequence through the winding switching system and the secondary winding 1s of the mutual inductor to be tested, and the remaining secondary windings are connected to the ground in parallel; the ammeter A2 is connected in series between the secondary winding of the test transformer and the remaining secondary windings of the mutual inductor to be tested. The present application can complete the switching of multiple windings on the withstand voltage device, and can realize the protection of the entire circuit by connecting an external 220V power supply and installing two sets of AC contactors in the platform, and is suitable for the secondary winding withstand voltage test of mutual inductors with a maximum of 6 windings.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of mutual inductor manufacturing, in particular to a mutual inductor automatic switching type winding withstand voltage test system and method. BACKGROUND

[0002] At present, the secondary winding withstand voltage test of the mutual inductor, the output end of the current withstand voltage equipment only has one high-voltage line, the high-voltage line is connected to the tested end in the test, and the other windings are short-circuited to the ground. If there are multiple secondary windings, the secondary windings need to be connected and tested one by one. In this operation process, the following disadvantages exist:

[0003] 1) The test voltage is about 3kV, if the secondary winding of the mutual inductor is too much, the voltage needs to be reduced multiple times, and the wiring needs to be manually connected. If the operation is not proper, it will pose a certain safety hazard to the wiring personnel and the product.

[0004] 2) If the secondary winding is too much, the test efficiency will also be greatly reduced, and the time is mainly wasted in checking the wiring, separating the secondary winding lead, and avoiding contact. The test efficiency is low. SUMMARY

[0005] In view of the above-mentioned deficiencies in the process of the secondary winding withstand voltage test of the mutual inductor in the prior art, the technical problem to be solved by the present application is to provide a mutual inductor automatic switching type winding withstand voltage test system and method which can improve the test efficiency, is safe and reliable, is easy to operate, and can eliminate safety hazards.

[0006] The technical scheme adopted by the present application to achieve the above-mentioned purpose is: a mutual inductor automatic switching type winding withstand voltage test system for detecting the secondary winding withstand voltage test of the mutual inductor to be tested, comprising: a power switch, a voltage regulator, a test transformer, a winding switching system, an ammeter A1, an ammeter A2, a voltmeter V1 and a voltmeter V2.

[0007] The voltage regulator is connected to a 220V power supply and controlled by the power switch to turn on and off the power supply. The primary side winding of the voltage regulator is connected to the input end of the primary side winding of the test transformer through the ammeter A1.

[0008] The secondary side winding of the test transformer is connected to the secondary winding 1s of the mutual inductor to be tested through the winding switching system in turn, and the remaining secondary windings of the mutual inductor to be tested are connected in parallel to the ground.

[0009] The ammeter A2 is connected in series between the secondary side winding of the test transformer and the remaining secondary windings of the mutual inductor to be tested, and is used to measure the primary current value between the secondary winding 1s of the mutual inductor to be tested and the ground.

[0010] The primary side winding of the test transformer comprises: a first primary side winding and a second primary side winding.

[0011] The first primary winding input end of the test transformer is connected in parallel with a voltmeter V1 for detecting the primary winding voltage of the test transformer;

[0012] The voltmeter V2 is connected in parallel across the second primary winding of the test transformer for detecting the secondary voltage of the secondary winding of the tested transformer.

[0013] The number of turns of the first primary winding is less than that of the second primary winding;

[0014] The number of turns of the first primary winding and the number of turns of the second primary winding are both less than the number of turns of the secondary winding of the test transformer.

[0015] The winding switching system comprises a winding changeover switch, a first AC contactor group and a second AC contactor group;

[0016] The input end of the winding changeover switch is connected to the high-voltage line led out from the secondary winding of the test transformer, and the output end is connected in series with the first AC contactor group and connected to the zero line;

[0017] The first AC contactor group and the second AC contactor group are interlocked;

[0018] The first AC contactor group comprises a plurality of first AC contactors connected in parallel, and a first normally open contact and a first normally closed contact corresponding to each first AC contactor;

[0019] The second AC contactor group comprises a plurality of second AC contactors corresponding to each first AC contactor connected in parallel, and a second normally open contact corresponding to each second AC contactor;

[0020] One end of each second AC contactor is connected to the zero line, and the other end is connected in series with the first normally closed contact and the first normally open contact of the corresponding first AC contactor in sequence, and then connected to the high-voltage line;

[0021] The plurality of first normally closed contacts are connected in parallel with the voltmeter V2;

[0022] Each second normally open contact is connected in parallel with the corresponding second AC contactor to the zero line.

[0023] It also includes a number of winding signal lamps corresponding to the number of first contactors;

[0024] Each winding signal lamp is connected in series with the first normally open contact, and when the first normally open contact is closed, the corresponding winding signal lamp is turned on.

[0025] The number of first AC contactors is the same as the number of windings of the tested transformer.

[0026] The tested transformer is a current transformer or a voltage transformer;

[0027] The to-be-tested mutual inductor is a single-winding mutual inductor or a multi-winding mutual inductor.

[0028] The power switch is an air switch; and the test transformer is a step-up transformer.

[0029] A voltage withstand test method of a mutual inductor automatic switching type winding voltage withstand test system, comprising the following steps:

[0030] 1) Start the voltage regulator, close the power switch, provide 220V power supply to the voltage regulator, the pointer of the power supply voltage points to 220V, and zero the voltage regulator;

[0031] 2) When the winding switching switch is turned to the nth winding corresponding to the to-be-tested mutual inductor, the signal lamp Dn corresponding to the winding signal lamp is turned on;

[0032] 3) In the process of voltage boosting, the output voltage of the voltage regulator is adjusted to the primary winding of the step-up transformer, the voltage value of the primary winding of the transformer is detected through the voltmeter V1, the high-voltage line is connected from the secondary winding of the transformer to the to-be-tested mutual inductor, the secondary voltage value of the secondary winding of the to-be-tested mutual inductor is detected through the voltmeter V2, and the state of the secondary winding is judged.

[0033] The secondary voltage value of the secondary winding of the to-be-tested mutual inductor is detected through the voltmeter V2, and the state of the secondary winding is judged, specifically as follows:

[0034] When the secondary voltage value of the secondary winding of the to-be-tested mutual inductor is instantaneously reduced to 0V and the primary current between the secondary winding of the to-be-tested mutual inductor and the ground detected by the ammeter A2 reaches the upper limit of the table, it is determined that the secondary winding of the to-be-tested mutual inductor is insulation breakdown, otherwise it meets the voltage withstand standard.

[0035] The step 2) is specifically as follows:

[0036] When the winding switching switch is turned to the nth winding corresponding to the to-be-tested mutual inductor, the first AC contactor CJ n is attracted, and the remaining first AC contactors are still disconnected, and then the first contactor CJ n corresponding to the first normally open contact E1 n is closed, and the remaining first normally open contacts are still disconnected.

[0037] The second contactor cj n is disconnected, and the remaining second contactors on the winding remain closed; the winding switching system is turned on, and the signal lamp D n corresponding to the winding signal lamp is turned on.

[0038] The first contactor CJ n corresponding to the first normally closed contact is disconnected, and the second contactor cj n corresponding to the second normally open contact E2n When the circuit is open, the second normally open contact on the remaining contacts closes, achieving a short-circuit grounding.

[0039] The present invention has the following beneficial effects and advantages:

[0040] 1. This invention enables multiple winding switching on a withstand voltage device, with an external 220V power supply, and is suitable for withstand voltage tests of the secondary windings of current transformers with up to 6 windings.

[0041] 2. Since the secondary withstand voltage test of the instrument transformer does not distinguish between test frequencies, it can complete the secondary withstand voltage test of the two internationally common frequencies (50Hz and 60Hz) of the instrument transformer. This facilitates high-voltage wiring of the secondary terminals of the instrument transformer, short-circuiting and grounding of the non-tested winding, and winding switching, which simplifies the secondary withstand voltage test process, improves the overall test safety factor, ensures personnel safety, and achieves one-time wiring without the need for secondary wiring inspection, thereby improving the efficiency of the secondary withstand voltage test.

[0042] 3. The core of this invention consists of a rotary switch and two sets of AC contactors working together. By utilizing the interlocking function of the contactors, the windings are automatically switched and the non-tested winding is short-circuited to ground, preventing the test transformer from being overloaded and short-circuited. Attached Figure Description

[0043] Figure 1 This is a control circuit diagram of the winding switching system in an embodiment of the present invention;

[0044] Figure 2 This is a high-voltage output circuit diagram of two sets of AC contactors in this invention;

[0045] Figure 3 This is a schematic diagram of the secondary withstand voltage electrical circuit of the current transformer in an embodiment of the present invention;

[0046] Figure 4 This is the monitoring panel for the device of the present invention. Detailed Implementation

[0047] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0048] like Figure 3 As shown, this invention is a schematic diagram of the secondary withstand voltage of a current transformer. This invention is used to test the withstand voltage of the secondary winding of a transformer under test, wherein the transformer under test is a current transformer or a voltage transformer; the transformer under test is a single-winding transformer or a multi-winding transformer.

[0049] In this embodiment, the transformer under test is a current transformer for secondary winding withstand voltage testing.

[0050] Among them, such as Figure 3As shown, the present application includes: a power switch, a voltage regulator T, a test transformer YD, a winding switching system, an ammeter A1, an ammeter A2, a voltmeter V1 and a voltmeter V2;

[0051] The voltage regulator is connected to a 220V power supply and the power supply is controlled by the power switch;

[0052] The primary winding of the voltage regulator is connected to the input end of the primary winding of the test transformer through the ammeter A1;

[0053] The secondary winding of the test transformer is connected to the high-voltage line, which is connected to the secondary winding 1s of the measured transformer through the winding switching system in turn, and the remaining secondary windings of the measured transformer are connected to the ground in parallel. The secondary windings of the measured transformer in this embodiment include the secondary windings 2s and 3s of the measured transformer, which are connected to the ground in parallel.

[0054] The ammeter A2 is connected in series between the secondary winding of the test transformer and the remaining secondary windings of the measured transformer, and is used to measure the primary current value between the secondary winding 1s of the measured transformer and the ground.

[0055] The primary winding of the test transformer includes a first primary winding and a second primary winding.

[0056] The number of turns of the first primary winding is less than that of the second primary winding, and the number of turns of both the first primary winding and the second primary winding is less than that of the secondary winding of the test transformer.

[0057] Since the test transformer YD is a step-up transformer, the number of turns of the first primary winding and the second primary winding in this embodiment is 300 turns and 600 turns respectively. The number of turns of the secondary winding of the test transformer in this embodiment is 3000 turns. By inputting low voltage through the voltage regulator T and outputting high voltage through the transformation ratio, the voltage is stepped up. The voltmeter V2 measures the secondary withstand voltage of the secondary winding of the measured transformer. In order to measure the secondary withstand voltage after step-down, the number of turns of the second primary winding is less than that of the secondary winding of the test transformer.

[0058] The input end of the first primary winding of the test transformer is connected in parallel with the voltmeter V1, which is used to detect the voltage of the primary winding of the test transformer.

[0059] The voltmeter V2 is connected in parallel across the second primary winding of the test transformer, which is used to detect the secondary withstand voltage of the secondary winding of the measured transformer.

[0060] Among them, the voltmeter V1 and the voltmeter V2 are square root voltage meters.

[0061] As shown in the figure, Figure 1As shown, it is the control circuit diagram of the winding switching system in the embodiment of the present application, the core part of the present application, the rotating switch and the two sets of AC contactors cooperate with each other, the winding automatic switching and the non-test winding short-circuit grounding are realized by using the interlocking function of the contactor.

[0062] The winding switching system comprises a winding conversion switch, a first AC contactor group and a second AC contactor group.

[0063] The winding conversion switch adopts a universal conversion switch LW5-16.

[0064] The input end of the winding conversion switch is connected to the high-voltage line led out by the secondary winding of the test transformer, the output end is connected in series with the first AC contactor group, and the zero line is connected.

[0065] The first AC contactor group and the second AC contactor group constitute interlocking.

[0066] The first AC contactor group comprises a plurality of first AC contactors connected in parallel, and a first normally open contact and a first normally closed contact corresponding to each first AC contactor.

[0067] The second AC contactor group comprises a plurality of second AC contactors corresponding to each first AC contactor connected in parallel, and a second normally open contact corresponding to each second AC contactor.

[0068] One end of each second AC contactor is connected to the zero line, and the other end is connected in series with the first normally closed contact and the first normally open contact of the corresponding first AC contactor in turn, and then connected to the high-voltage line.

[0069] The plurality of first normally closed contacts are connected in parallel with the voltmeter V2.

[0070] The AC contactors all adopt CJ20-16 220V AC contactors.

[0071] As shown in the high-voltage output circuit diagram of the present application, each second normally open contact is connected in parallel with the corresponding second AC contactor to the zero line. Figure 2

[0072] The number of first AC contactors is the same as the number of windings of the mutual inductor to be tested.

[0073] In the embodiment, the multi-winding current mutual inductor with the maximum winding of 6 windings is detected, so in the embodiment, the number of first AC contactors is 6.

[0074] The winding switching system further comprises a winding signal lamp corresponding to the number of first contactors, and the model of the signal lamp is AD16-22 / 31 220V. ​

[0075] Each winding signal lamp is in series with the first normally open contact, and when the first normally open contact is closed, the corresponding winding signal lamp is turned on.

[0076] As shown in the figure, the winding pressure test method of the automatic switching type mutual inductor winding pressure test system comprises the following steps: Figure 3

[0077] 1) Start the voltage regulator, close the power switch, and provide 220V power to the voltage regulator. The pointer of the power voltage points to 220V, and the voltage regulator is adjusted to zero.

[0078] 2) When the winding switch is turned to the nth winding corresponding to the mutual inductor to be tested, the winding signal lamp corresponding to the signal lamp D n lights up;

[0079] 3) During the voltage boosting process, adjust the output voltage of the voltage regulator to the primary winding of the voltage boosting transformer. Detect the voltage value of the primary winding of the transformer through the voltmeter V1. Connect the high-voltage line from the secondary winding of the transformer to the mutual inductor to be tested. Detect the secondary voltage value of the secondary winding of the mutual inductor to be tested through the voltmeter V2, and judge the state of the secondary winding.

[0080] The secondary voltage value of the secondary winding of the mutual inductor to be tested is detected by the voltmeter V2, and the state of the secondary winding is judged. Specifically:

[0081] When the secondary voltage value of the secondary winding of the mutual inductor to be tested detected by the voltmeter V2 is instantaneously reduced to 0V, and the primary current between the secondary winding of the mutual inductor to be tested and the ground detected by the ammeter A2 reaches the upper limit of the table, it is determined that the secondary winding of the mutual inductor to be tested is insulation breakdown, otherwise it meets the pressure standard.

[0082] Step 2) is specifically:

[0083] When the winding switch is turned to the nth winding corresponding to the mutual inductor to be tested, the first AC contactor CJ n is attracted, and the remaining first AC contactors are still open, and then the first contactor CJ n corresponding to the first normally open contact E1 n is closed, and the remaining first normally open contacts are still open;

[0084] The second contactor cj n is opened, and the remaining winding second contactors remain closed; the winding switching system is turned on, and the winding signal lamp corresponding to the signal lamp D n lights up;

[0085] The first contactor CJ n corresponding to the first normally closed contact is opened, and the second contactor cj n corresponding to the second normally open contact E2 n ​Break, the second normally open contact on the rest of the closing, short circuit ground.

[0086] As Figure 4 shown, the monitoring panel of the present application includes: 220V power supply voltage, primary voltage measured by voltmeter V1, primary current measured by ammeter A2 in the test transformer, and secondary withstand voltage of the secondary winding of the transformer under test measured by voltmeter V2, and the above detection data are reflected on the respective pointer ammeter; and winding interconnection state indicator lamp.

[0087] The present embodiment takes the CJ1 winding as an example, and the operating principle of the present application is as follows:

[0088] After starting the test, first close the power air switch to provide 220V power supply for the equipment, and the pointer of the power supply voltage points to 220V, i.e. Figure 4 the power supply voltage displayed on the monitoring panel; at this time, the pointer of the voltmeter V1 is still 0V, ensuring that the voltage regulator is zero (zero position indicator light is on), and in this embodiment, the fuse protects the entire equipment, isolates the external 220V power supply from the entire equipment, and avoids the impact of external power surge on the equipment at the moment of closing.

[0089] The reverse group switching switch is realized by Figure 1 rotating the switch, and the interlocking function is realized by using the rotating switch in cooperation with the AC contactor. When the rotating switch is rotated to Figure 4 1a group, Figure 1 the first contactor CJ1 is attracted (i.e. Figure 2 the first contactor CJ1 is attracted, and the first contactors CJ2-CJ6 remain open), and the first contactors CJ2-CJ6 are open; Figure 1 the first normally open contact of the contactor CJ1 is closed, the first normally closed contact is open, and the first normally open and closed contacts of the other windings CJ2-CJ6 remain unchanged; Figure 4 the 1a group signal lamp is on;

[0090] At the same time, Figure 1 the second contactor CJ1 is open, and the other winding contactors CJ2-CJ6 remain closed Figure 2 , the second normally open contact of CJ1 is still open, the second contactors CJ2-CJ6 are closed, and the short circuit ground is shorted), ensuring that the other windings are shorted to N (ground line), and in turn, the automatic winding switching withstand voltage test can be realized.

[0091] During the voltage boosting process, adjust the output voltage of the voltage regulator T to the primary winding of the voltage boosting transformer, monitor the voltage of the secondary winding of the transformer, and the primary voltage, and connect the high voltage line from the secondary winding of the transformer to the test object. During the test, the voltmeter V2 displays Figure 4 the test voltage in the secondary winding, i.e. the secondary withstand voltage;

[0092] If, during the test, voltmeter V2 detects that the secondary withstand voltage of the secondary winding of the transformer under test drops instantaneously to 0V ( Figure 4 When the test voltage suddenly drops to 0V, the primary current pointer of the output current meter reaches its maximum, that is: when the primary current between the secondary winding of the transformer under test and ground reaches the upper limit of the meter after 1 second (the test voltage) is detected by ammeter A2. Figure 4 If the current is too high (e.g., if the secondary winding insulation of the transformer under test is broken down), the power circuit breaker should be switched off to ensure the safety of personnel and equipment. Then, the secondary winding should be short-circuited with a grounding wire to discharge the voltage. Otherwise, it meets the withstand voltage standard.

Claims

1. An automatic switching type winding withstand voltage test system of a transformer for detecting a secondary winding withstand voltage test of a transformer to be tested, characterized by, The utility model relates to a kind of transformer automatic switching type winding withstand voltage test system and its withstand voltage test method. The transformer automatic switching type winding withstand voltage test system comprises a power switch, a voltage regulator, a test transformer, a winding switching system, an ammeter A1, an ammeter A2, a voltmeter V1 and a voltmeter V2. The voltage regulator is connected to a 220V power supply and controlled by the power switch. The primary winding of the voltage regulator is connected to the input end of the primary winding of the test transformer through the ammeter A1. The secondary winding of the test transformer is connected to the secondary winding 1s of the transformer to be tested through the winding switching system in sequence. The ammeter A2 is connected in series between the secondary winding of the test transformer and the remaining secondary windings of the transformer to be tested. The input end of the first primary winding of the test transformer is connected in parallel to the voltmeter V1 for detecting the voltage of the primary winding of the test transformer. The voltmeter V2 is connected in parallel to the second primary winding of the test transformer for detecting the secondary withstand voltage of the secondary winding of the transformer to be tested. The winding switching system comprises a winding switching switch, a first AC contactor group and a second AC contactor group. The input end of the winding switching switch is connected to the high-voltage line from the secondary winding of the test transformer, and the output end is connected in series to the first AC contactor group and the zero line. The first AC contactor group and the second AC contactor group are interlocked. The first AC contactor group comprises a plurality of first AC contactors connected in parallel, and a first normally open contact and a first normally closed contact corresponding to each first AC contactor. The second AC contactor group comprises a plurality of second AC contactors corresponding to each first AC contactor connected in parallel, and a second normally open contact corresponding to each second AC contactor. One end of each second AC contactor is connected to the zero line, and the other end is connected in series to the first normally closed contact and the first normally open contact of the corresponding first AC contactor in sequence, and then connected to the high-voltage line. A plurality of first normally closed contacts are connected in parallel to the voltmeter V2. Each second normally open contact is connected in parallel to the corresponding second AC contactor and the zero line. The number of first AC contactors is the same as the number of windings of the transformer to be tested. The withstand voltage test method of the transformer automatic switching type winding withstand voltage test system comprises the following steps: 1) Start the voltage regulator, close the power switch, provide 220V power supply to the voltage regulator, the pointer of the power supply voltage points to 220V, and adjust the voltage regulator to zero. 2) when the winding switch goes to the nth winding corresponding to the mutual inductor to be tested, the signal lamp D corresponding to the winding signal lamp lights up; n ​ 3) During the voltage boosting process, adjust the output voltage of the voltage regulator to the primary winding of the voltage boosting transformer, detect the voltage value of the primary winding of the transformer through the voltmeter V1, connect the high-voltage line from the secondary winding of the transformer to the transformer to be tested, detect the secondary withstand voltage of the secondary winding of the transformer to be tested through the voltmeter V2, and judge the state of the secondary winding. The detection of the secondary withstand voltage of the secondary winding of the transformer to be tested through the voltmeter V2 and the judgment of the state of the secondary winding are as follows: When the voltage meter V2 detects that the secondary voltage of the secondary winding of the tested mutual inductor instantaneously drops to 0V and the ammeter A2 detects that the primary current between the secondary winding 1s of the tested mutual inductor and the ground reaches the upper limit of the meter, it is determined that the secondary winding of the tested mutual inductor is insulation breakdown, otherwise, it meets the voltage resistance standard.

2. The automatic switching type winding withstand voltage test system of a transformer according to claim 1, characterized in that, The number of turns of the first primary winding is less than the number of turns of the second primary winding. The number of turns of the first primary winding and the number of turns of the second primary winding are both less than the number of turns of the secondary winding of the test transformer.

3. The automatic switching type winding withstand voltage test system of a transformer according to claim 1, characterized in that, The winding signal lamp corresponding to the number of the first contactors is further included; Each winding signal lamp is connected in series with the first normally open contact, and the corresponding winding signal lamp is turned on after the first normally open contact is closed.

4. The automatic switching type winding withstand voltage test system of a transformer according to claim 1, characterized in that, The tested mutual inductor is a current transformer or a voltage transformer. The tested mutual inductor is a single-winding mutual inductor or a multi-winding mutual inductor.

5. The automatic switching type winding withstand voltage test system of a transformer according to claim 1, characterized in that, The power switch is an air switch, and the test transformer is a step-up transformer.

6. The automatic switching type winding withstand voltage test system of a transformer according to claim 1, characterized in that, The step 2) is specifically: Turning to the nth winding of the winding switch to the corresponding to-be-tested mutual inductor, the first AC contactor CJ n suction, the remaining first AC contactor is still open, and then the first contactor CJ n The corresponding first normally open contact E1 n closed, the remaining first normally open contact is still open; second contactor cj n open, the second contactor on the remaining winding remains closed; the winding switching system is turned on, the winding signal light corresponding to the signal light D n lit up; The first contactor CJ n The corresponding first normally closed contact opens, the second contactor CJ n The corresponding second normally open contact E2 n opens, the rest of the second normally open contacts on the top close, realizing a short circuit to ground.

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